From: Michael Niedermayer <mich...@niedermayer.cc> Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> --- libavfilter/internal.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/libavfilter/internal.h b/libavfilter/internal.h index a7ec751..fcd1a5a 100644 --- a/libavfilter/internal.h +++ b/libavfilter/internal.h @@ -305,8 +305,25 @@ int ff_poll_frame(AVFilterLink *link); /** * Request an input frame from the filter at the other end of the link. * + * The source filter may pass the request on to its sources, fullfill the + * request from an internal buffer or any other means specific to its function. + * When the end of a stream is reached AVERROR_EOF is returned and no further frames. + * When a filter is unable to output a frame for example due to its sources + * being unable to do so or because it depends on external means pushing data + * into it then AVERROR(EAGAIN) is returned. + * One example of a source returning AVERROR(EAGAIN) is a buffer into which the + * user application pushes new data, it cannot fullfill a request + * or know its at EOF until the user application has given it this + * information + * + * If a request is successfull then the filter_frame() function will be called + * at least once before ff_request_frame() returns + * * @param link the input link * @return zero on success + * AVERROR_EOF on end of file + * AVERROR(EAGAIN) if the previous filter cannot output a frame + * currently and can neither gurantee that EOF has been reached. */ int ff_request_frame(AVFilterLink *link); -- 1.7.9.5 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
